Pair.java

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.aries.spifly;

/**
 * A simple holder object for a pair of objects.
 */
public class Pair <A, B> {
    private final A left;
    private final B right;

    public Pair(A left, B right) {
        this.left = left;
        this.right = right;
    }

    public A getLeft() {
        return left;
    }

    public B getRight() {
        return right;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((left == null) ? 0 : left.hashCode());
        result = prime * result + ((right == null) ? 0 : right.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        
        Pair<?, ?> other = (Pair<?, ?>) obj;
        if (left == null) {
            if (other.left != null)
                return false;
        } else if (!left.equals(other.left))
            return false;
        if (right == null) {
            if (other.right != null)
                return false;
        } else if (!right.equals(other.right))
            return false;
        return true;
    }

    @Override
    public String toString() {
        return "Pair [left=" + left + ", right=" + right + "]";
    }    
}